test-cogl-pixel-array: fix how data is initialized
test-cogl-pixel-array: fix how data is initialized

There was a missing '* 4' and '* i' in the for() loops that initialized
the first test buffer, so it was containing uninitialized data causing
the test to fail.

Distrotech/clutter,jigpu/clutter,heysion/clutter-clone,spatulasnout/clutter,ebassi/clutter,Distrotech/clutter,heysion/clutter-clone,spatulasnout/clutter,rkudiyarov/clutter_osx,collects/clutter,ebassi/clutter,kerrickstaley/clutter-vala,rkudiyarov/clutter_osx,djdeath/clutter-android,jigpu/clutter,dlespiau/clutter,djdeath/clutter,Distrotech/clutter,djdeath/clutter,jigpu/clutter,djdeath/clutter-android,nobled/clutter,heysion/clutter-clone,djdeath/clutter-multithreaded,rkudiyarov/clutter_osx,GNOME/clutter,collects/clutter,djdeath/clutter-android,dlespiau/clutter,spatulasnout/clutter,GNOME/clutter,djdeath/clutter-multithreaded,ebassi/clutter,ebassi/clutter,djdeath/clutter-multithreaded,ebassi/clutter,djdeath/clutter,collects/clutter,Distrotech/clutter,spatulasnout/clutter,djdeath/clutter-android,djdeath/clutter,GNOME/clutter,nobled/clutter,heysion/clutter-clone,jigpu/clutter,heysion/clutter-clone,djdeath/clutter,GNOME/clutter,jigpu/clutter,kerrickstaley/clutter-vala,collects/clutter,djdeath/clutter,GNOME/clutter,rkudiyarov/clutter_osx,djdeath/clutter-multithreaded,Distrotech/clutter,spatulasnout/clutter,dlespiau/clutter,jigpu/clutter,djdeath/clutter-android,kerrickstaley/clutter-vala,nobled/clutter,Distrotech/clutter,kerrickstaley/clutter-vala,collects/clutter